1. Field Of The Invention
The field of the present invention is suspension systems for automobiles, and particularly, an improvement in the suspension system for automobiles comprising a pair of upper and lower control arms which are linked to a knuckle carrying a wheel and are pivotally connected at their base ends to a vehicle body for vertical swinging movement.
2. Description Of The Prior Art
A double wishbone type suspension system is widely known (for example, see Japanese Patent publication No. 28123/69).
In such a prior art suspension system, the base ends of the upper and lower control arms are pivotally connected to a horizontal shaft fixedly mounted on a vehicle body through elastic support members, respectively and hence, a longitudinal compliance and a caster rigidity during braking are governed by the spring constant of the elastic members.
In general, in order to prevent, a shock, produced when a wheel goes over a protrusion on a road surface, from being transmitted to the vehicle body. It is necessary to increase the longitudinal compliance of the suspension system. In addition, in order to insure a straight advancing property of the wheel, it is necessary to increase the caster rigidity of the suspension system.
In the above prior art suspension system, however, if the spring constant of the elastic member is set smaller to provide a larger longitudinal compliance, the caster rigidity is reduced to degrade the straight advancing property of the wheel. On the other hand, if the spring constant of the elastic member is set larger to provide a larger caster rigidity during braking, the longitudinal compliance is reduced, accompanied by an adverse deterioration of the riding comfort. Therefore, it is difficult to satisfy both of the longitudinal compliance and the caster rigidity during braking.
Even if a non-linear spring characteristic is provided to the elastic support members, it is impossible to insure longitudinal compliance during braking.